refactor(simulation): rename DistrictSkeleton→QuarterSkeleton per D-222 (#950)

D-222 renamed the 512m generation cell from District to Quarter (District
is now a new 2048m tier above it). Align the generation skeleton code to
the canonical vocabulary. Pure naming — no behavior change; all 1296 lib
tests + integration tests pass unchanged.

Renamed (spatial-cell identifiers):
- DistrictSkeleton → QuarterSkeleton, DistrictWorldState → QuarterWorldState
- DistrictId → QuarterId, DistrictContext/DistrictBoundaries → Quarter*
- field district_id → quarter_id, district_type → quarter_type
- BodyWorldState.districts map → .quarters
- generate_skeleton → generate_quarter_skeleton

Deliberately left as-is (these name functional ZONING, not the spatial
tier — orthogonal to D-222): DistrictType, DistrictLayoutMode, the
district_mix module (DistrictMix/compute_district_mix), and the
GenWorkItem::GenerateSkeleton / GenCompletion::SkeletonGenerated variants.

Also aligned the perception "sim tile" → "subtile" vocabulary (D-222:
Subtile = 0.5m) in decisions/perception.md and the generation-cascade code
comments. Historical D-066/D-094/D-201/D-220 decision bodies keep their
existing D-222 amendment notes (not rewritten in place); the public
max_offset_sim_tiles fn name is unchanged.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

decisions/perception.md

@@ -149,7 +149,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 ### D-044: Art direction — visual hierarchy (entity > object > structure)
 - **Date:** 2026-02-12
 - **Decision:** Three-layer visual hierarchy: entities (2px outline, D-033 relationship color, highest saturation) > objects (1px outline, era-appropriate palette, moderate saturation) > structure (minimal/no outline, muted zone palette, lowest saturation). Hard rendering rule: entity always wins visual ties — if an entity and object overlap, the entity's D-033 color must remain visible. This is a readability guarantee, not an aesthetic preference.
-- **Entity spec:** 24x32 pixel footprint within 64x64px visual tiles. Entities occupy 1x1 sim tiles (0.5m) but render across a 2x2 sim tile sprite footprint per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor). D-033 color as primary information signal, silhouette as primary identity signal. One identifying silhouette feature per named NPC (Kael's vest, Lera's apron, Sera's uniform). 3-4 template silhouettes for generic NPCs.
+- **Entity spec:** 24x32 pixel footprint within 64x64px visual tiles. Entities occupy 1x1 subtiles (0.5m) but render across a 2x2 subtile sprite footprint per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor). D-033 color as primary information signal, silhouette as primary identity signal. One identifying silhouette feature per named NPC (Kael's vest, Lera's apron, Sera's uniform). 3-4 template silhouettes for generic NPCs.
 - **Canonical reference:** `docs/workshops/art-direction-mood-board/workshop-outcomes.md` §1.4, §1.5
 - **Raised by:** Araminta (outline spec), Ozzie (readability priority). Unanimously endorsed.
 - **Dissent:** None
@@ -212,7 +212,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
   - **Object hover:** Ticks rotate 45° to X-shape. Muted grey #8b8ba0 (amber #e8c547 if flagged). Simpler frame than entity.
   - **Weapon aim:** Hard transition. Ticks extend, center gap widens, lines thicken 1→2px. Warm white #f0e8d8. NO bloom. Entity in sights tints to D-033 color — aiming at a friend (green tint) should feel wrong.
 - All transitions 150ms linear. z-layer 7. Never changes by zone or narrative state ([D-045](#d-045-art-direction--environmental-neutrality-strict-zero-shift)).
-- Cursor changes on LOS, not just proximity. Click interaction range: ~2 sim tiles (= 1m per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)). Weapon-selected mode suppresses interaction prompts unless Shift held ("combat intent trumps social intent").
+- Cursor changes on LOS, not just proximity. Click interaction range: ~2 subtiles (= 1m per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)). Weapon-selected mode suppresses interaction prompts unless Shift held ("combat intent trumps social intent").
 - **Diegetic test (Stig):** Interaction labels render on z-layer 6 (insert overlay). If the insert is off, labels disappear. Passes the "is this information from the character's implant?" test.
 - **Rationale:** Diegetic — cursor is the insert's own interface element. Consistent with [D-048](#d-048-neural-insert-overlay--visual-design). Entity in weapon sights tinting to D-033 creates moral friction.
 - **Cross-reference:** Insert overlay ([D-048](#d-048-neural-insert-overlay--visual-design)), entity color ([D-033](#d-033-entity-color--relationship-to-player)), z-stack ([D-049](#d-049-z-level-rendering-stack-8-layers))
@@ -254,7 +254,7 @@ How the player observes and interacts with the world: camera, fog, line-of-sight
 ### D-059: Fog — shader-based, five layers, knowledge-graph-driven
 - **Date:** 2026-02-13
 - **Decision:** Fog is a shader-driven system (not particles) with five distinct layers:
-  1. **Clear (vision cone):** Soft gradient edge over 6-8 sim tiles (= 3-4 visual tiles per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)), no hard line. Darkwood approach.
+  1. **Clear (vision cone):** Soft gradient edge over 6-8 subtiles (= 3-4 visual tiles per [D-066](architecture.md#d-066-dual-scale-grid--05m-simulation-1m-visual-2x-retina-factor)), no hard line. Darkwood approach.
   2. **Light fog (peripheral):** Desaturated 40-50%, brightness -30%. Animated Perlin noise overlay (8-10s cycle). Entity [D-033](#d-033-entity-color--relationship-to-player) colors visible but reduced.
   3. **Deep fog (previously explored):** Near-monochrome with ~10% "zone temperature" tint (bar=warm dark, hub=cool dark, corridor=neutral dark). More pronounced noise (15-20s cycle). Fog breathes.
   4. **Unexplored + maps app:** Geometric wireframe outlines #333340. Insert data aesthetic.

server/src/atlas/block_irregularity.rs

@@ -45,7 +45,7 @@ fn archetype_step_bp(archetype: &PoliticalArchetype) -> i32 {
     }
 }
 
-/// Derive the maximum block offset in sim tiles from `block_irregularity`.
+/// Derive the maximum block offset in subtiles from `block_irregularity`.
 ///
 /// Used by `DistrictLayoutMode::Organic`: `max_offset = (irregularity × 16.0) as i16`.
 pub fn max_offset_sim_tiles(irregularity: f32) -> i16 {

server/src/atlas/body_world_state.rs

@@ -14,7 +14,7 @@ use bevy_ecs::prelude::Resource;
 use serde::{Deserialize, Serialize};
 
 use crate::atlas::attractor_matching::CityPlacement;
-use crate::simulation::generator::{DistrictId, DistrictWorldState, GeographicAttractor};
+use crate::simulation::generator::{GeographicAttractor, QuarterId, QuarterWorldState};
 
 /// Simulation tick counter — monotonically increasing u64.
 pub type SimTick = u64;
@@ -75,11 +75,11 @@ pub struct BodyWorldState {
     /// Settlement placements (D-211, #955). Attractor-matched city positions.
     /// Empty until the Layer-3 placement task completes.
     pub placements: Vec<CityPlacement>,
-    /// District-level world state, keyed by `DistrictId` (D-230).
+    /// Quarter-level world state, keyed by `QuarterId` (D-230).
     ///
     /// Populated by `GenCompletion::SkeletonGenerated` after the plan phase
     /// completes for each city. `BTreeMap` for D-010 determinism.
-    pub districts: BTreeMap<DistrictId, DistrictWorldState>,
+    pub quarters: BTreeMap<QuarterId, QuarterWorldState>,
     /// Last sim tick this entry was read. Used for LRU eviction.
     pub last_accessed: SimTick,
 }
@@ -201,7 +201,7 @@ mod tests {
             drainage_basins: vec![],
             attractors: vec![],
             placements: vec![],
-            districts: BTreeMap::new(),
+            quarters: BTreeMap::new(),
             last_accessed: tick,
         }
     }

server/src/atlas/cascade.rs

@@ -88,7 +88,7 @@ impl CascadeSnapshot {
             drainage_basins,
             attractors,
             placements,
-            districts: std::collections::BTreeMap::new(),
+            quarters: std::collections::BTreeMap::new(),
             last_accessed: 0,
         }
     }

server/src/atlas/gen_queue.rs

@@ -12,7 +12,7 @@
 //!
 //! **Work item types (D-206):**
 //! - `AnalyzeBody`:       D8 drainage + attractor extraction for a body.
-//! - `GenerateSkeleton`:  Phase 1 DistrictSkeleton for a city.
+//! - `GenerateSkeleton`:  Phase 1 QuarterSkeleton for a city.
 //! - `FillChunk`:         Phase 2 chunk fill for a pre-loaded district.
 //!
 //! Completion events are delivered to the main thread via
@@ -31,9 +31,9 @@ use crate::atlas::attractor_matching::CityRecord;
 use crate::atlas::body_world_state::BodyWorldState;
 use crate::atlas::cascade::{run_cascade_from_heightmap, CascadeLayer};
 use crate::atlas::heightmap::{load_heightmap_png, GRID_H, GRID_W};
-use crate::atlas::skeleton_gen::generate_skeleton;
+use crate::atlas::skeleton_gen::generate_quarter_skeleton;
 use crate::seed::SeedChain;
-use crate::simulation::generator::{CityGenerationContext, DistrictWorldState};
+use crate::simulation::generator::{CityGenerationContext, QuarterWorldState};
 
 // ---------------------------------------------------------------------------
 // Priority
@@ -73,7 +73,7 @@ pub enum GenWorkItem {
         /// (#955); empty if the body has no settlements (cascade stops at Layer 1).
         cities: Vec<CityRecord>,
     },
-    /// Generate a Phase 1 DistrictSkeleton for this city.
+    /// Generate a Phase 1 QuarterSkeleton for this city.
     ///
     /// `context` is the D-199 economic read-set pre-resolved at dispatch time.
     /// All 6 required fields must be populated before this item is submitted
@@ -83,11 +83,11 @@ pub enum GenWorkItem {
     /// `body_id` routes the resulting `SkeletonGenerated` completion into the
     /// correct `BodyWorldState` cache entry (D-230).
     ///
-    /// `district_id` is the stable content-addressable id for the generated
+    /// `quarter_id` is the stable content-addressable id for the generated
     /// district (keyed by city position + world seed).
     ///
     /// `economic_role`, `population`, and `founding_age_years` are D-199 fields
-    /// carried alongside the context because `generate_skeleton` accepts them as
+    /// carried alongside the context because `generate_quarter_skeleton` accepts them as
     /// separate parameters (its signature is not changed by this ticket).
     GenerateSkeleton {
         city_id: u64,
@@ -95,17 +95,17 @@ pub enum GenWorkItem {
         /// D-199 economic read-set + all other context fields.
         context: Box<CityGenerationContext>,
         /// Stable content-addressable district id (D-194/D-230).
-        district_id: u64,
+        quarter_id: u64,
         /// District-level seed chain (D-224).
         chain: SeedChain,
-        // D-199 raw fields passed to generate_skeleton separately.
+        // D-199 raw fields passed to generate_quarter_skeleton separately.
         economic_role: String,
         population: i64,
         founding_age_years: u32,
     },
     /// Pre-fill a chunk in an existing district.
     FillChunk {
-        district_id: u64,
+        quarter_id: u64,
         block_pos: (u32, u32),
     },
 }
@@ -135,14 +135,14 @@ pub enum GenCompletion {
     SkeletonGenerated {
         city_id: u64,
         /// The body this skeleton belongs to — used to route state into
-        /// `BodyWorldState.districts` (D-230).
+        /// `BodyWorldState.quarters` (D-230).
         body_id: String,
         /// District-level world state (skeleton + block tags) produced by the plan phase (D-230).
         /// Boxed to keep `GenCompletion` variant sizes balanced (D-230 skeleton is ~2.7 KB).
-        state: Box<DistrictWorldState>,
+        state: Box<QuarterWorldState>,
     },
     ChunkFilled {
-        district_id: u64,
+        quarter_id: u64,
         block_pos: (u32, u32),
     },
     /// Work item failed — body_id or city_id for logging.
@@ -385,7 +385,7 @@ fn run_work_item(item: &GenWorkItem) -> GenCompletion {
             city_id,
             body_id,
             context,
-            district_id,
+            quarter_id,
             chain,
             economic_role,
             population,
@@ -394,29 +394,29 @@ fn run_work_item(item: &GenWorkItem) -> GenCompletion {
             // Build the Phase 1 skeleton from the pre-resolved D-199 context.
             // `economic_role`, `population`, and `founding_age_years` are the
             // D-199 raw fields carried alongside the context because
-            // `generate_skeleton` accepts them as separate parameters.
-            let skeleton = generate_skeleton(
+            // `generate_quarter_skeleton` accepts them as separate parameters.
+            let skeleton = generate_quarter_skeleton(
                 context,
                 *population,
                 economic_role,
-                *district_id,
+                *quarter_id,
                 *founding_age_years,
                 *chain,
             );
             GenCompletion::SkeletonGenerated {
                 city_id: *city_id,
                 body_id: body_id.clone(),
-                state: Box::new(DistrictWorldState {
+                state: Box::new(QuarterWorldState {
                     skeleton,
                     block_tags: std::collections::BTreeMap::new(),
                 }),
             }
         }
         GenWorkItem::FillChunk {
-            district_id,
+            quarter_id,
             block_pos,
         } => GenCompletion::ChunkFilled {
-            district_id: *district_id,
+            quarter_id: *quarter_id,
             block_pos: *block_pos,
         },
     }
@@ -493,7 +493,7 @@ mod tests {
                 dominant_bulk_class: BulkClass::NonPhysical,
                 dominant_production_ubiquity: ProductionUbiquity::Common,
             }),
-            district_id: city_id * 10,
+            quarter_id: city_id * 10,
             chain: SeedChain::root(42 + city_id),
             economic_role: "service_mixed".to_string(),
             population: 500_000,
@@ -590,7 +590,7 @@ mod tests {
         let q = make_queue();
         q.submit(
             GenWorkItem::FillChunk {
-                district_id: 99,
+                quarter_id: 99,
                 block_pos: (0, 0),
             },
             GenPriority::High,

server/src/atlas/layer_proxy.rs

@@ -228,7 +228,7 @@ mod tests {
             drainage_basins: vec![],
             attractors: vec![],
             placements: vec![],
-            districts: std::collections::BTreeMap::new(),
+            quarters: std::collections::BTreeMap::new(),
             last_accessed: 0,
         });
         let (_db, resolver) = empty_resolver();

server/src/atlas/plugin.rs

@@ -93,16 +93,16 @@ fn drain_generation_completions(
             } => {
                 if !body_id.is_empty() {
                     if let Some(body_state) = cache.peek_mut(&body_id) {
-                        // Key by state.skeleton.district_id (D-194/D-230): a city has many
-                        // districts, each with its own DistrictId. `city_id` is only the
+                        // Key by state.skeleton.quarter_id (D-194/D-230): a city has many
+                        // quarters, each with its own QuarterId. `city_id` is only the
                         // dispatch key used in the work item — the canonical insert key is
-                        // the district's own stable id. TODO(#957): the stub GenerateSkeleton
-                        // returns a default skeleton with district_id=0; real gen (#957) will
+                        // the quarter's own stable id. TODO(#957): the stub GenerateSkeleton
+                        // returns a default skeleton with quarter_id=0; real gen (#957) will
                         // populate it from CityGenerationContext.
-                        let _ = city_id; // used as dispatch key only; district_id is the map key
+                        let _ = city_id; // used as dispatch key only; quarter_id is the map key
                         body_state
-                            .districts
-                            .insert(state.skeleton.district_id, *state);
+                            .quarters
+                            .insert(state.skeleton.quarter_id, *state);
                     } else {
                         tracing::warn!(
                             city_id,

server/src/atlas/skeleton_gen.rs

@@ -1,8 +1,8 @@
-//! Phase 1 district skeleton generator (D-194, D-196, D-211, D-213, D-214).
+//! Phase 1 quarter skeleton generator (D-194, D-196, D-211, D-213, D-214).
 //!
-//! Entry point: [`generate_skeleton`].  Consumes a [`CityGenerationContext`]
+//! Entry point: [`generate_quarter_skeleton`].  Consumes a [`CityGenerationContext`]
 //! together with the city's raw population and economic role, and produces a
-//! fully classified [`DistrictSkeleton`] with:
+//! fully classified [`QuarterSkeleton`] with:
 //!
 //! - [`SettingType`] derived from the surrounding biome context.
 //! - [`ComplexityTier`] derived from population tier × [`WorldTier`].
@@ -22,8 +22,8 @@ use crate::atlas::block_irregularity::block_irregularity;
 use crate::atlas::district_mix::{compute_district_mix, population_tier};
 use crate::seed::{SeedChain, SeedDomain};
 use crate::simulation::generator::{
-    BlockPlacement, BlockSkeleton, CityGenerationContext, ComplexityTier, DistrictId,
-    DistrictLayoutMode, DistrictSkeleton, DistrictType, MultiBlockReservation, PoliticalArchetype,
+    BlockPlacement, BlockSkeleton, CityGenerationContext, ComplexityTier, DistrictLayoutMode,
+    DistrictType, MultiBlockReservation, PoliticalArchetype, QuarterId, QuarterSkeleton,
     ReservationFunction, ReservationId, SettingType, WorldTier, ZoningType,
 };
 
@@ -31,23 +31,23 @@ use crate::simulation::generator::{
 // Public API
 // ---------------------------------------------------------------------------
 
-/// Generate a Phase 1 [`DistrictSkeleton`] from a city's generation context.
+/// Generate a Phase 1 [`QuarterSkeleton`] from a city's generation context.
 ///
 /// # Parameters
 /// - `context`: Build-time city context (archetype, world tier, orientation…).
 /// - `population`: Raw population count from atlas_city_names.
 /// - `economic_role`: Economic role string (one of the 10 canonical values).
-/// - `district_id`: Content-addressable identifier for this district.
+/// - `quarter_id`: Content-addressable identifier for this district.
 /// - `founding_age_years`: Years since founding — controls block irregularity.
 /// - `chain`: This district's position in the deterministic seed tree (D-224 SeedChain).
-pub fn generate_skeleton(
+pub fn generate_quarter_skeleton(
     context: &CityGenerationContext,
     population: i64,
     economic_role: &str,
-    district_id: DistrictId,
+    quarter_id: QuarterId,
     founding_age_years: u32,
     chain: SeedChain,
-) -> DistrictSkeleton {
+) -> QuarterSkeleton {
     // ── 1. SettingType ────────────────────────────────────────────────────
     // Pass through the surrounding_biome from context — it already encodes
     // the planet/station/wilderness classification established at atlas time.
@@ -103,11 +103,11 @@ pub fn generate_skeleton(
     // Reserved blocks carry their own z_levels count.
     let z_levels: u8 = 1;
 
-    DistrictSkeleton {
-        district_id,
+    QuarterSkeleton {
+        quarter_id,
         seed: chain.seed(),
-        district_type: district_type_from_mix(&primary_district_type),
-        context: String::new(), // stub — DistrictContext = String
+        quarter_type: district_type_from_mix(&primary_district_type),
+        context: String::new(), // stub — QuarterContext = String
         world_tier: context.world_tier.clone(),
         complexity,
         setting,
@@ -242,7 +242,7 @@ fn derive_layout_mode(
 /// Generate 4×4 organic block placements seeded deterministically (D-010).
 ///
 /// Uses a seeded LCG; offset range controlled by `irregularity` (0.05–1.0)
-/// scaled to the ±16 sim tile maximum from `block_irregularity::max_offset_sim_tiles`.
+/// scaled to the ±16 subtile maximum from `block_irregularity::max_offset_sim_tiles`.
 fn organic_placements(irregularity: f32, chain: SeedChain) -> [[BlockPlacement; 4]; 4] {
     let max_offset = (irregularity * 16.0) as i16;
     // id = 0: one placement pass per district. Sibling separation comes from the
@@ -292,7 +292,7 @@ fn zoning_for_district(dt: &DistrictType) -> ZoningType {
     }
 }
 
-/// Map the primary district type to the DistrictType field on DistrictSkeleton.
+/// Map the primary district type to the DistrictType field on QuarterSkeleton.
 fn district_type_from_mix(primary: &DistrictType) -> DistrictType {
     primary.clone()
 }
@@ -437,14 +437,15 @@ mod tests {
     fn setting_station_passthrough() {
         let mut ctx = make_context(PoliticalArchetype::Commission, WorldTier::Regional);
         ctx.surrounding_biome = SettingType::Station;
-        let sk = generate_skeleton(&ctx, 500_000, "institutional", 1, 200, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 500_000, "institutional", 1, 200, SeedChain::root(42));
         assert!(matches!(sk.setting, SettingType::Station));
     }
 
     #[test]
     fn setting_urban_for_city_on_planet() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Regional);
-        let sk = generate_skeleton(&ctx, 500_000, "financial", 1, 200, SeedChain::root(42));
+        let sk = generate_quarter_skeleton(&ctx, 500_000, "financial", 1, 200, SeedChain::root(42));
         assert!(matches!(sk.setting, SettingType::Urban));
     }
 
@@ -452,14 +453,15 @@ mod tests {
     fn complexity_epicenter_high_pop_is_full() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Epicenter);
         // 10M pop → pop_tier = 1 → Full on Epicenter
-        let sk = generate_skeleton(&ctx, 10_000_000, "financial", 1, 200, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 10_000_000, "financial", 1, 200, SeedChain::root(42));
         assert_eq!(sk.complexity, ComplexityTier::Full);
     }
 
     #[test]
     fn complexity_waypoint_tiny_pop_is_empty() {
         let ctx = make_context(PoliticalArchetype::Pioneer, WorldTier::Waypoint);
-        let sk = generate_skeleton(&ctx, 1_000, "residential", 1, 50, SeedChain::root(42));
+        let sk = generate_quarter_skeleton(&ctx, 1_000, "residential", 1, 50, SeedChain::root(42));
         assert_eq!(sk.complexity, ComplexityTier::Empty);
     }
 
@@ -467,7 +469,7 @@ mod tests {
     fn complexity_backwater_low_pop_is_moderate() {
         let ctx = make_context(PoliticalArchetype::Pioneer, WorldTier::Backwater);
         // 50_000 pop → pop_tier = 0 → Moderate on Backwater (D-218: not budget-capped)
-        let sk = generate_skeleton(&ctx, 50_000, "residential", 1, 50, SeedChain::root(42));
+        let sk = generate_quarter_skeleton(&ctx, 50_000, "residential", 1, 50, SeedChain::root(42));
         assert_eq!(sk.complexity, ComplexityTier::Moderate);
     }
 
@@ -475,7 +477,8 @@ mod tests {
     fn complexity_backwater_high_pop_is_full() {
         let ctx = make_context(PoliticalArchetype::Pioneer, WorldTier::Backwater);
         // 10M pop → pop_tier = 1 → Full on Backwater (D-218: not budget-capped)
-        let sk = generate_skeleton(&ctx, 10_000_000, "residential", 1, 50, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 10_000_000, "residential", 1, 50, SeedChain::root(42));
         assert_eq!(sk.complexity, ComplexityTier::Full);
     }
 
@@ -483,28 +486,31 @@ mod tests {
     fn complexity_passage_low_pop_is_minimal() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Passage);
         // 50_000 pop → pop_tier = 0 → Minimal on Passage (transit stop, budget-capped)
-        let sk = generate_skeleton(&ctx, 50_000, "transit_hub", 1, 100, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 50_000, "transit_hub", 1, 100, SeedChain::root(42));
         assert_eq!(sk.complexity, ComplexityTier::Minimal);
     }
 
     #[test]
     fn layout_commission_is_grid() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Regional);
-        let sk = generate_skeleton(&ctx, 500_000, "institutional", 1, 100, SeedChain::root(99));
+        let sk =
+            generate_quarter_skeleton(&ctx, 500_000, "institutional", 1, 100, SeedChain::root(99));
         assert!(matches!(sk.layout_mode, DistrictLayoutMode::Grid));
     }
 
     #[test]
     fn layout_pioneer_is_organic() {
         let ctx = make_context(PoliticalArchetype::Pioneer, WorldTier::Regional);
-        let sk = generate_skeleton(&ctx, 500_000, "residential", 1, 400, SeedChain::root(99));
+        let sk =
+            generate_quarter_skeleton(&ctx, 500_000, "residential", 1, 400, SeedChain::root(99));
         assert!(matches!(sk.layout_mode, DistrictLayoutMode::Organic { .. }));
     }
 
     #[test]
     fn block_grid_is_fully_populated() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Regional);
-        let sk = generate_skeleton(&ctx, 500_000, "financial", 1, 200, SeedChain::root(42));
+        let sk = generate_quarter_skeleton(&ctx, 500_000, "financial", 1, 200, SeedChain::root(42));
         // All 16 blocks must have valid positions.
         for row in 0..4 {
             for col in 0..4 {
@@ -519,7 +525,7 @@ mod tests {
     fn no_reservations_for_small_city() {
         let ctx = make_context(PoliticalArchetype::Pioneer, WorldTier::Backwater);
         // pop_tier 0, not transit_hub → no reservations.
-        let sk = generate_skeleton(&ctx, 80_000, "residential", 1, 50, SeedChain::root(42));
+        let sk = generate_quarter_skeleton(&ctx, 80_000, "residential", 1, 50, SeedChain::root(42));
         assert!(sk.reservations.is_empty());
     }
 
@@ -527,7 +533,8 @@ mod tests {
     fn park_reservation_for_large_city() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Epicenter);
         // 100M pop → pop_tier 2 → park reservation.
-        let sk = generate_skeleton(&ctx, 100_000_000, "financial", 1, 300, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 100_000_000, "financial", 1, 300, SeedChain::root(42));
         let has_park = sk
             .reservations
             .iter()
@@ -539,7 +546,8 @@ mod tests {
     fn transit_terminal_for_transit_hub_role() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Regional);
         // pop_tier 0 but transit_hub → terminal reservation.
-        let sk = generate_skeleton(&ctx, 80_000, "transit_hub", 1, 200, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 80_000, "transit_hub", 1, 200, SeedChain::root(42));
         let has_terminal = sk
             .reservations
             .iter()
@@ -551,7 +559,8 @@ mod tests {
     fn reserved_blocks_linked_in_grid() {
         let ctx = make_context(PoliticalArchetype::Commission, WorldTier::Epicenter);
         // 100M pop → park at (1,2),(1,3),(2,2),(2,3) with reservation id 1.
-        let sk = generate_skeleton(&ctx, 100_000_000, "financial", 1, 300, SeedChain::root(42));
+        let sk =
+            generate_quarter_skeleton(&ctx, 100_000_000, "financial", 1, 300, SeedChain::root(42));
         // All park blocks must reference the park reservation (id=1).
         for &(row, col) in &[(1u8, 2u8), (1, 3), (2, 2), (2, 3)] {
             let b = &sk.blocks[row as usize][col as usize];
@@ -565,7 +574,7 @@ mod tests {
     #[test]
     fn determinism_same_seed_same_output() {
         let ctx = make_context(PoliticalArchetype::Industrial, WorldTier::Regional);
-        let sk1 = generate_skeleton(
+        let sk1 = generate_quarter_skeleton(
             &ctx,
             2_000_000,
             "manufacturing",
@@ -573,7 +582,7 @@ mod tests {
             250,
             SeedChain::root(12345),
         );
-        let sk2 = generate_skeleton(
+        let sk2 = generate_quarter_skeleton(
             &ctx,
             2_000_000,
             "manufacturing",

server/src/npc/blueprint.rs

@@ -9,7 +9,7 @@
 //! - `NpcBlueprint` — generator output for a single NPC
 //!
 //! Plus `SpikeOutput` as the top-level binary output container.
-//! These are spike-specific and intentionally decoupled from `DistrictSkeleton`.
+//! These are spike-specific and intentionally decoupled from `QuarterSkeleton`.
 //!
 //! ## Content contract
 //!
@@ -547,7 +547,7 @@ pub enum RelationshipValence {
 
 /// Top-level output for the generator spike binary.
 ///
-/// Intentionally decoupled from `DistrictSkeleton` — this is a proof-of-life
+/// Intentionally decoupled from `QuarterSkeleton` — this is a proof-of-life
 /// container, not production architecture.
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct SpikeOutput {

server/src/simulation/generator.rs

@@ -1,6 +1,6 @@
-//! World generator data model — district skeleton and mobile chunk types.
+//! World generator data model — quarter skeleton and mobile chunk types.
 //!
-//! Phase 1 generator output: the `DistrictSkeleton` produced by the world generation
+//! Phase 1 generator output: the `QuarterSkeleton` produced by the world generation
 //! pipeline. Consumed by Phase 2 (chunk fill) and by the simulation startup path.
 //!
 //! **D-110 (signed z-levels):** All z-level *position* fields use `i8` (negative values
@@ -24,7 +24,7 @@ use serde::{Deserialize, Serialize};
 // ---------------------------------------------------------------------------
 
 /// Unique district identifier (content-addressable via hash of world position + seed).
-pub type DistrictId = u64;
+pub type QuarterId = u64;
 /// Unique multi-block reservation identifier within a district.
 pub type ReservationId = u64;
 /// Unique social site identifier within a district.
@@ -55,13 +55,13 @@ pub type ChunkLayout = String;
 /// Corridor spine connecting district access points. Stub.
 pub type CorridorSpine = String;
 /// District context — neighboring districts, world position, system. Stub.
-pub type DistrictContext = String;
+pub type QuarterContext = String;
 /// Society profile reference (Miri's cultural ingredients). Stub.
 pub type SocietyProfileRef = String;
 /// Zone definition — base palette + modifiers + zone name. Stub.
 pub type ZoneDefinition = String;
 /// District boundary system — edge descriptors with neighbors. Stub.
-pub type DistrictBoundaries = String;
+pub type QuarterBoundaries = String;
 /// Guarantee audit result — tier-appropriate spatial invariant checks. Stub.
 pub type GuaranteeAuditResult = String;
 /// District access point (entry/exit to neighboring district). Stub.
@@ -939,17 +939,17 @@ pub enum ProductionUbiquity {
     MonopolySource,
 }
 
-/// District-level world state produced by the plan phase (D-230).
+/// Quarter-level world state produced by the plan phase (D-230).
 ///
 /// Output of `GenerateSkeleton` extended to include building-property tags.
-/// Stored in `BodyWorldState.districts: BTreeMap<DistrictId, DistrictWorldState>`.
+/// Stored in `BodyWorldState.quarters: BTreeMap<QuarterId, QuarterWorldState>`.
 /// `BTreeMap` for D-010 determinism.
 ///
-/// D-230: `{ skeleton: DistrictSkeleton, block_tags: BTreeMap<(u8,u8), Vec<BuildingPropertyTag>> }`
+/// D-230: `{ skeleton: QuarterSkeleton, block_tags: BTreeMap<(u8,u8), Vec<BuildingPropertyTag>> }`
 #[derive(Serialize, Deserialize, Clone, Debug, Default, PartialEq)]
-pub struct DistrictWorldState {
+pub struct QuarterWorldState {
     /// Phase 1 skeleton produced by `GenerateSkeleton` (D-230).
-    pub skeleton: DistrictSkeleton,
+    pub skeleton: QuarterSkeleton,
     /// Building property tags keyed by block position (row, col) within the 4×4 grid.
     /// Each entry is a Vec of one tag per building footprint placed in that block.
     /// `BTreeMap` for D-010 determinism (no HashMap non-determinism).
@@ -999,7 +999,7 @@ pub struct CityGenerationContext {
 /// Organic layout placement for a single block.
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq, Default)]
 pub struct BlockPlacement {
-    /// Offset from grid-aligned position (±16 sim tiles per axis max).
+    /// Offset from grid-aligned position (±16 subtiles per axis max).
     pub offset: (i16, i16),
     /// Rotation in 15° increments (0–3, max 45°).
     pub rotation_steps: u8,
@@ -1008,8 +1008,8 @@ pub struct BlockPlacement {
     pub street_width_bps: u16,
 }
 
-/// Single block within a district's 4×4 block grid.
-/// Each block = 128×128 sim tiles = 2×2 chunks.
+/// Single block within a quarter's 4×4 block grid.
+/// Each block = 128×128 subtiles = 2×2 chunks.
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default)]
 pub struct BlockSkeleton {
     /// Grid position (0–3, 0–3).
@@ -1160,10 +1160,10 @@ pub struct MultiBlockReservation {
 }
 
 // ---------------------------------------------------------------------------
-// District skeleton
+// Quarter skeleton
 // ---------------------------------------------------------------------------
 
-/// Phase 1 generator output for one district.
+/// Phase 1 generator output for one quarter.
 ///
 /// Produced by the async background generation pipeline.
 /// Consumed by Phase 2 (chunk-by-chunk fill, on demand) and by
@@ -1171,8 +1171,8 @@ pub struct MultiBlockReservation {
 ///
 /// ## Z-level naming convention (D-110)
 ///
-/// - `z_levels: u8` — how many floor levels exist in this district (count, always ≥ 1)
-/// - `base_z` does not appear on `DistrictSkeleton` itself — the district's
+/// - `z_levels: u8` — how many floor levels exist in this quarter (count, always ≥ 1)
+/// - `base_z` does not appear on `QuarterSkeleton` itself — the quarter's
 ///   ground level is always 0. Sub-ground structures use [`MultiBlockReservation`]
 ///   with a negative `base_z` field.
 ///
@@ -1181,14 +1181,16 @@ pub struct MultiBlockReservation {
 /// All `Vec<_>` fields are stable-ordered at generation time (sorted by a
 /// deterministic key). Generation reproduces identical output for the same seed.
 #[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default)]
-pub struct DistrictSkeleton {
+pub struct QuarterSkeleton {
     // ── Identity ──────────────────────────────────────────
-    pub district_id: DistrictId,
+    pub quarter_id: QuarterId,
     /// Deterministic seed (derived from master seed via SeedChain).
     pub seed: u64,
-    pub district_type: DistrictType,
+    /// The quarter's primary functional zone (still a `DistrictType` — the
+    /// zoning vocabulary is orthogonal to the spatial tier, D-222).
+    pub quarter_type: DistrictType,
     /// World context (system, world, neighboring districts).
-    pub context: DistrictContext,
+    pub context: QuarterContext,
 
     // ── Classification ────────────────────────────────────
     pub world_tier: WorldTier,
@@ -1197,7 +1199,7 @@ pub struct DistrictSkeleton {
     pub layout_mode: DistrictLayoutMode,
 
     // ── Spatial Structure ─────────────────────────────────
-    /// The 4×4 block grid (each block = 128×128 sim tiles = 2×2 chunks).
+    /// The 4×4 block grid (each block = 128×128 subtiles = 2×2 chunks).
     pub blocks: [[BlockSkeleton; 4]; 4],
     /// Multi-block reservations (skyscrapers, parks, terminals, plazas).
     pub reservations: Vec<MultiBlockReservation>,
@@ -1215,7 +1217,7 @@ pub struct DistrictSkeleton {
     pub zone_palette: Vec<ZoneDefinition>,
 
     // ── Boundary System ───────────────────────────────────
-    pub boundaries: DistrictBoundaries,
+    pub boundaries: QuarterBoundaries,
 
     // ── Validation ────────────────────────────────────────
     /// Guarantee audit result. `None` for Empty districts.
@@ -1367,9 +1369,9 @@ mod tests {
         assert_eq!(r.z_levels, 30u8, "z_levels count must remain u8");
     }
 
-    /// D-110: z_levels (count) remains u8 on DistrictSkeleton.
+    /// D-110: z_levels (count) remains u8 on QuarterSkeleton.
     #[test]
-    fn district_skeleton_z_levels_is_unsigned() {
+    fn quarter_skeleton_z_levels_is_unsigned() {
         // Verify z_levels is u8 (cannot hold negative value). Static assertion:
         // if this compiled with z_levels = 255u8, the type is correct.
         fn assert_u8(_: u8) {}